Organic salts and their use as reagents in electrochemical reactions

ABSTRACT

Use of an organic compound salt of general formula 
 
A-XY   (I) 
wherein A means an organic residue, X means a charged group and Y means a counter-ion, as a reagent in an electrochemical reaction and organic compound salt corresponding to the formula 
 
R1R2ZC-T-Q-XY 
wherein X is a charged group, Y is a counter-ion, Z is a group capable of being substituted, R1 and R2 mean organic residues, T means a group containing a hetero atom selected among N-R4, O and S, and Q means a connecting group linking the hetero atom and the charged group.

The present invention concerns the use of organic compounds as reagentsin electrochemical reactions and a process for producing an organicsubstance comprising an electrochemical reaction stage.

Electrochemical reactions are used industrially for producing certaincommodities such as for example adiponitrile, certain fine chemicalsubstances such as anisaldehyde or anthraquinone and certainspecialities such as cysteine or picolinic acid.

Technical criteria important for the economics of such processesinclude, among others, a high chemical yield, a high electrochemicalyield, low energy consumption, a high concentration of the startingsubstances in the electrochemical reaction medium, good electrodestability, long membrane life, ease of isolation of the product and thepossibility of recycling the electrolyte comprising solvent and aconducting salt.

The patent application DE-2842760 describes the methylation ofN-alkylated urethanes in the α position by electrochemical oxidation inmethanolic solution in the presence of a conducting salt.

It was desirable to find an electrochemical reaction usable in theproduction of substances and to a maximal extent meeting the aforesaidcriteria.

The invention thus concerns the use of an organic compound salt ofgeneral formulaA-XY   (I)wherein A means an organic residue, X means a charged group and Y meansa counter-ion, as a reagent in an electrochemical reaction.

Surprisingly, it has been found that the use according to the inventionmakes it possible to improve the efficiency of electrochemicalreactions, in particular as regards their chemical and electrochemicalyield and their energy consumption. The use according to the inventionmakes it possible to carry out electrochemical reactions in a mediumhaving a high concentration of reactant. The use according to theinvention ensures good conductivity of the reaction medium for theelectrochemical reaction. The electrochemical reaction can be effectedin the substantial absence of conducting salts. The isolation of theproduct can be easily effected, the latter often appearing in acrystallisable form.

“Reagent” is intended to mean a compound which is used as such in thereaction. This is different from the formation of charged species whichcould take place in the course of an electrochemical reaction fromorganic compounds other than salts.

“Electrochemical reaction” is intended to mean in particular a reactioncomprising an electron transfer between the organic compound salt and anelectrode and the formation or cleavage of at least one covalent bond ofthe organic compound salt which has undergone the electron transfer.Typical reactions include the formation of a C—H bond, of a C—C bond orof a C-hetero atom bond. The formation of C—O bonds is preferred.

In the organic compound salt, the group A is an organic residue.

“Organic residue” is intended to mean any group which can contain linearor branched alkyl or alkylene groups, which may include hetero atomssuch as in particular atoms of boron, silicon, nitrogen, oxygen andsulphur. It can also contain cycloalkyl or cycloalkylene groups,heterocycles and aromatic systems. The organic residue can containdouble or triple bonds and functional groups.

The organic residue contains at least 1 carbon atom. Often, it containsat least 2 carbon atoms. Preferably, it contains at least 3 carbonatoms. More particularly preferably, it contains at least 5 carbonatoms.

The organic residue generally contains at most 100 carbon atoms. Often,it contains at most 50 carbon atoms. Preferably, it contains at most 40carbon atoms. More particularly preferably, it contains at most 30carbon atoms.

“Alkyl group” is intended to mean in particular a linear or branchedalkyl substituent containing from 1 to 20 carbon atoms, preferably 1, 2,3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. Specific examples of suchsubstituents are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,tert-butyl, n-pentyl, isopentyl, n-hexyl, 2-hexyl, n-heptyl, n-octyl andbenzyl.

“Cycloalkyl group” is intended to mean in particular a substituentcontaining at least one saturated carbon ring with 3 to 10 carbon atoms,preferably 5, 6 or 7 carbon atoms. Specific examples of suchsubstituents are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl andcycloheptyl.

“Alkylene group” or “cycloalkylene group” are intended to mean inparticular bivalent radicals derived from alkyl groups or cycloalkylgroups as defined above.

When the organic residue contains one or possibly several double bonds,it is often selected among an alkenyl or cycloalkenyl group containingfrom 2 to 20 carbon atoms, preferably 2, 3, 4, 5, 6, 7, 8, 9 or 10carbon atoms. Specific examples of such groups are vinyl, 1-allyl,2-allyl, n-but-2-enyl, isobutenyl, 1,3-butadienyl, cyclopentenyl,cyclohexenyl and styryl.

When the organic residue contains one or possibly several triple bonds,it is often selected among an alkynyl group containing from 2 to 20carbon atoms, preferably 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms.Specific examples of such groups are ethynyl, 1-propynyl, 2-propynyl,n-but-2-ynyl and 2-phenylethynyl.

When the organic residue contains one or possibly several aromaticsystems, it is often an aryl group containing from 6 to 24 carbon atoms,preferably from 6 to 12 carbon atoms. Specific examples of such groupsare phenyl, 1-tolyl, 2-tolyl, 3-tolyl, xylyl, 1-naphthyl and 2-naphthyl.

“Heterocycle” is intended to mean in particular a cyclic systemcontaining at least one saturated or unsaturated ring formed of 3, 4, 5,6, 7 or 8 atoms of which at least one is a hetero atom. The hetero atomis often selected among B, N, O, Si, P and S. More often, it is selectedamong N, O and S.

The heterocycle often corresponds to the formula

wherein J and L are independently selected among C, N, O and S and m andn independently have values from 0 to 4, preferably 1, 2 or 3.

Specific examples of such heterocycles are aziridine, azetidine,pyrrolidine, piperidine, morpholine, 1,2,3,4-tetrahydroquinoline,1,2,3,4-tetrahydroisoquinoline, perhydroquinoline, perhydroisoquinoline,(1H)-indole, isoxazolidine, pyrazoline, imidazoline, thiazoline, furan,tetrahydrofuran, thiophen, tetrahydrothiophen, pyran, tetrahydropyranand dioxan.

The organic residues as defined above can be unsubstituted orsubstituted with functional groups. Functional group is intended to meanin particular a substituent containing or consisting of a hetero atom.The hetero atom is often selected among B, N, O, Al, Si, P, S, Sn, Asand Se and the halogens. More often, it is selected among N, O, S and P,in particular N, O and S.

The functional group generally contains 1, 2, 3, 4, 5 or 6 atoms.

As functional groups, for example halogens, a hydroxy group, an alkoxygroup, a mercapto group, an amino group, a nitro group, a carbonylgroup, an acyl group, an optionally esterified carboxyl group, acarboxamide group, a urea group, a urethane group and the thiolatedderivatives of the groups containing a carbonyl group mentioned above, aphosphine, phosphonate or phosphate group, a sulphoxide group, asulphone group and a sulphonate group may be cited.

In particular, the group A can also form a cyclic system with the groupX. A group A containing atoms of nitrogen and/or of oxygen, and inparticular heterocycles containing these atoms, is preferred. The groupA is generally an organic residue containing at least one atom activatedfor an electrochemical reaction.

In the organic compound salt, the group X is a cationic or anionicgroup. A cationic group is preferred.

The group X often contains at least one atom from groups 13, 15 or 16 ofthe periodic table of the elements. A group X containing at least oneatom from groups 13 or 15 of the periodic table of the elements ispreferred. Among these atoms, those of the second and third period aremore particularly preferred. A group X containing at least one atom ofnitrogen or of sulphur is quite particularly preferred.

In a first specific aspect, the group X corresponds to the formulaN—C(═NH)—NH₂ ⁺. Specific examples of organic compound salts containingthis group are selected among the derivatives of arginine, in particularthe N^(α)-protected amides of arginine, for example with a heterocyclecontaining nitrogen as defined above.

In a second specific aspect, the group X corresponds to the formula SR₂⁺ in which R signifies organic residues, in particular as defined above,it being understood that these residues can be identical or different orform a ring between themselves or with the group A. Particularlysuitable as R are alkyl, cycloalkyl or aryl groups such as defined aboveand more particularly a methyl group. Specific examples of organiccompound salts containing this group are selected among the derivativesof S-alkylmethionine, in particular the N^(α)-protected amides ofS-methyl-methionine, possibly enantiomerically pure, for example with aheterocycle containing nitrogen as defined above.

When the group X is a cationic group, it preferably corresponds to theformula —NR₃ ⁺, in which R is one or several organic residues, inparticular as defined above, it being understood that these residues canbe identical or different or form a ring between themselves or with thegroup A. Particularly suitable as R are alkyl, cycloalkyl or aryl groupsor groups forming a heterocycle with nitrogen, as defined above. Alkylgroups and groups forming a heterocycle with nitrogen are moreparticularly preferred.

Among the trialkylamino groups, the trimethylamino, triethylamino,diethylmethylamino and diethylisopropylamino groups are preferred.

Among the groups forming a heterocycle with nitrogen, thosecorresponding to the above formula (II) containing a nitrogen atombearing an alkyl group as defined above, in particular selected amongmethyl and ethyl, are preferred.

Among the groups forming a ring with the group A, we may cite inparticular those corresponding to the formula

wherein R is as defined above, m is 0, 1, 2 or 3, n is 1 or 2, L isselected among C, O, S and N and A′ is a part of the residue A.

The above groups of formula —NR₃ ⁺ can be obtained for example fromtrisubstituted amines by reaction with a precursor containing a groupcapable of being replaced by nucleophilic substitution, such as Cl.

In the organic chemical salt, the group Y is generally an externalcounter-ion, that is to say it is not linked by a covalent bond to thegroup A-X.

The group Y is at least one cation or at least one anion having thepolarity opposite to that of the group X. An anionic group is preferred.Monovalent anions are particularly preferred.

As anions, in particular the halogens, complex inorganic anions such aspolyfluorinated or polyoxo anions, and organic anions such as inparticular the organic sulphonates may be cited. The group Y can beselected, preferably among Br⁻, Cl^(—), ClO₄ ⁻, BF₄ ⁻, PF₆ ⁻,toluene-sulphonate (Tos⁻) and benzenesulphonate (PhSO3⁻). A group Yselected among Cl⁻, ClO₄ ⁻, BF₄ ⁻ and PF₆ ⁻ is particularly preferred.

As cations, in particular inorganic or organic cations can be cited. Anorganic cation is preferred. A tetraalkylammonium cation, such astetraethylammonium or tetra(n-butyl)ammonium is particularly preferred.

In a first mode of use according to the invention, the group Y comprisesat least one anion or at least one cation, in particular monovalent,which is inert under the conditions of the electrochemical reaction.Among the anions which are generally stable under the conditions of theelectrochemical reaction, in particular the complex inorganic anionssuch as polyfluorinated or polyoxo anions, and organic anions such as inparticular organic sulphonates may be cited. The anions BF₄ ⁻, PF₆ ⁻,toluenesulphonate (Tos⁻) and benzenesulphonate (PhSO3⁻) are preferred.As cations, the tetraalkylammonium cations cited above are verysuitable.

In this mode, the content of inert anion or cation is generally greaterthan or equal to 50% by weight of the total weight of the group Y. Thiscontent is often greater than or equal to 75% by weight of the totalweight of the group Y. This is content is preferably greater than orequal to 90% by weight of the total weight of the group Y. In this mode,the group Y can consist essentially of one inert anion or of one inertcation.

It has been found that this mode makes it possible to obtainparticularly good electrochemical and chemical yields and makes itpossible to attain a particularly high concentration of organic compoundsalt in organic solvents.

In a particular aspect, the content of inert anion or cation is lessthan or equal to 99.5% by weight of the total weight of the group Y. Inthis aspect, the content of inert anion or cation is preferably lessthan or equal to 97% by weight of the total weight of the group Y. Inthis particular aspect, the residual part of the group Y advantageouslyconsists of at least one anion or at least one cation capable of beingconverted into a reactive species under the conditions of theelectrochemical reaction. Examples of such anions are the halogens,especially Br⁻ and Cl⁻ and in particular Cl⁻.

Preferably, the group Y is a mixture consisting essentially on the onehand of at least one ion selected among ClO₄ ⁻, BF₄ ⁻, PF₆ ⁻, Tos⁻ andPhSO3⁻ and on the other hand of Cl⁻.

This particular aspect makes it possible to improve the selectivity andproductivity of indirect electrochemical reactions in which an activespecies such as a means of oxidation or of reduction, capable of reacting with an organic compound, is generated in situ by theelectrochemical route. This aspect also makes it possible to work in theabsence of supplementary quantities of anion or of cation capable ofbeing converted into a reactive species, extrinsic to the group Y of theorganic compound salt.

The invention also concerns the organic compound salt corresponding tothe first mode of use according to the invention and to this particularaspect.

In a second mode of use according to the invention, the organic compoundsalt corresponds to the formulaR1R2R3C-T-Q-XY   (IV)wherein

-   R1R2R3C means a substituted carbon atom, capable of reacting in the    electrochemical reaction,-   T means an activating group for the electrochemical reaction and-   Q means a connecting group linking the activating group T and the    charged group X.

In the group R1R2R3C, R1 and R2 independently signify hydrogen atoms,organic residues as defined above or R1 and R2 together form organicresidues as defined above. At least one of R1 or R2 can form a ring withthe group X, the group Q or the group T.

The group R3 is a group capable of being modified in the course of theelectrochemical reaction. R3 can for example signify a double bondformed with the group T or one of the groups R1 or R2. R3 is preferablyselected among —COOH and a hydrogen atom. A hydrogen atom is moreparticularly preferred.

The activating group T is generally a hetero atom, as described above inthe context of the description of the functional groups. The group T ispreferably selected among NR4, O and S. An NR4 group is quiteparticularly preferred.

R4 means a hydrogen atom or an organic residue as defined above. R4 canform a ring with the substituent R1 or R2. Preferably, R4 is selectedamong an alkyl or cycloalkyl group as defined above. Particularlypreferably, R4 with R1 or R2 forms a heterocycle corresponding to theformula above.

The connecting group Q is generally selected among a linear or branchedalkylene or cyclo-alkene group as defined above, preferably containingfrom 1 to 12 carbon atoms, possibly substituted with a functional groupas described above.

Preferably, the group Q is a possibly substituted polymethylene groupcontaining 1, 2, 3, 4, 5, 6, 7 or 8 carbon atoms. Such a groupcontaining 1, 2, 3 or 4 carbon atoms is quite particularly preferred.

The group Q preferably contains a functional group such as describedabove which links it to the group T. It has been found that the presenceof a functional group linking the group Q to the group T is particularlyuseful when it is desired to carry out subsequent reactions with theproduct from the electrochemical reaction, for example with the aim ofseparating the charged group from it. The functional group can alsoexert a supplementary activating effect and a stabilising effect in thecourse of the electrochemical reaction.

Specific examples of functional groups linking the group Q to the groupT are selected among —(C═O)—, —N—(C═O)—, —O—(C═O)—, —(S═O)—, —N—(S═O)—,—SO₂—, —N—SO₂—, —(C═S)— and —N—(C═S)—. A functional group selected among—(C═O)—, —N—(C═O)—, —O—(C═O)— and —SO₂— is preferred. A functional groupselected among —(C═O)— and —SO₂— is quite particularly preferred. It isintended to mean that the bond on the right hand side of the functionalgroups as indicated above is linked to the group T.

In a particularly preferred implementation mode, the organic compoundsalt corresponds to the formulaR1R2R3C—NR4-Q-NR₃ ⁺Y⁻,   (V)the substituents being defined above. Particularly preferred examples ofthe organic compound salt correspond to the following formulae in whichthe substituents are as defined above:

In a third mode of use according to the invention, the organic compoundsalt includes at least one stereogenic centre, in particular the organiccompound salt contains a centre of chirality.

This mode is particularly useful when one or several chiral centres areformed in the course of the electrochemical reaction or in the course ofpossible subsequent reactions. The diastereomers formed can then easilybe separated, and use made of diastereoselective reactions.

In the third use mode according to the invention, the organic compoundsalt is preferably enantiomerically pure.

“Enantiomerically pure organic compound salt” is intended to mean achiral organic compound salt consisting essentially of one enantiomer.The enantiomeric excess (ee) is defined as: ee (%)=100 (x₁−x₂)/(x₁+x₂)with x₁>x₂; x₁ and x₂ represent the content of enantiomer 1 or 2respectively in the mixture.

Generally, an enantiomerically pure organic compound salt with anenantiomeric excess greater than or equal to 99% is used. Anenantiomerically pure organic compound salt with an enantiomeric excessgreater than or equal to 99.5% is preferred. Particularly preferably, anenantiomerically pure organic compound salt with an enantiomeric excessgreater than or equal to 99.9% is used.

The use of an enantiomerically pure organic compound salt makes itpossible to obtain organic compounds and in particular electrochemicalreaction products exhibiting a high enantiomeric excess.

Specific examples of enantiomerically pure organic compound salts arefor example amides of trialkylbetaines of natural or non-natural aminoacids such as in particular amides of stachydrine or carnitine. Otheramino acid derivatives containing a charged group are mentioned above.

The invention also concerns a process for production of an organiccompound comprising

-   -   (a) a stage wherein a solution containing an organic compound        salt meeting the above description in a solvent is prepared    -   (b) a stage wherein the solution is subjected to electrolysis in        the presence of at least one co-reactant under conditions        sufficient to form the product of reaction of the organic        compound salt with the co-reactant.

In the process according to the invention, the stage (b) can for examplebe an electroreduction or an electrooxidation. Preferably, the stage (b)is an electrooxidation.

In the process according to the invention, the stage (b) can be effectedin a compartmented or non-compartmented cell.

The electrodes used in the stage (b) must be resistant to the conditionsof the electrochemical reaction. Appropriate materials are selected inparticular among metals, metal oxides and graphite. Particularlyappropriate metals are selected among steel, iron or titanium and inparticular among the platinum group metals and their oxides, orelectrodes coated with these latter materials. Platinum or rhodium ispreferred. An electrode containing platinum is particularly appropriate.

The distance between the electrodes is generally at least 0.2 mm. Often,this distance is at least 0.5 mm. Preferably it is at lest 1 mm. Thedistance between the electrodes is generally at most 20 mm. Often, thisdistance is at most 10 mm. Preferably it is at most 5 mm.

In the process according to the invention, the stage (b) is generallyeffected at a current density greater than or equal to 0.1 A/dm². Often,the current density is greater than or equal to 1 A/dm². Preferably, itis greater than or equal to 3 A/dm² In the process according to theinvention, the stage (b) is generally effected at a current density lessthan or equal to 50 A/dm². Often, the current density is less than orequal to 30 A/dM². Preferably, it is less than or equal to 20 A/dm².

In the process according to the invention, the stage (b) is generallyeffected at a temperature greater than or equal to −50° C. Often, thetemperature is greater than or equal to −20° C. Preferably, it isgreater than or equal to 0° C. In the process according to theinvention, the stage (b) is generally effected at a temperature lessthan or equal to 100° C. Often, the temperature is less than or equal to80° C. Preferably, it is less than or equal to 60° C.

In the process according to the invention, the concentration of organiccompound salt in the solution used in the stage (b) is generally greaterthan or equal to 0.1 moles/l . Often, this concentration is greater thanor equal to 0.2 moles/l. Preferably, it is greater than or equal to 0.25moles/l. In the process according to the invention, the concentration oforganic compound salt in the solution used in the stage (b) is generallyless than or equal to 3 moles/l. Often, this concentration is less thanor equal to 2 moles/l. Preferably, it is less than or equal to 1 mole/l.

Solvents usable in the process according to the invention are generallycapable of completely dissolving the desired quantity of organiccompound salt at the temperature of the reaction. Examples of usablesolvents include water, polar organic solvents and homogeneous mixturesof water with polar organic solvents.

In a first aspect, the solvent is inert under the conditions of theelectrochemical reaction. In this case, the solution generally alsocontains a co-reactant capable of reacting with the organic compoundsalt having undergone an electron transfer.

In a second aspect, the solvent is itself such a co-reactant. In thisaspect, the solvent preferably consists essentially of co-reactant.

It has been found that it is possible to limit the number ofconstituents of the reaction medium of the process according to theinvention to a minimum and to facilitate further the separation andpurification of the product of the electrochemical reaction.

The co-reactant capable of being the solvent is often selected amongwater, alcohols, carboxylic acids and mixtures thereof. The co-reactantis preferably selected among water, methanol, ethanol and acetic acid.Methanol is quite particularly preferred.

Acetic acid is also particularly preferred, especially when the organiccompound salt contains an, optionally protected, arginine as describedabove.

In a quite particularly preferred mode of the process according to theinvention, the organic compound salt corresponds to the formula (V) andthe co-reactant is methanol.

The process according to the invention can be performed in the virtualabsence of the conducting salt. In this case the concentration ofconducting salt is-generally less than 0.01 moles/l of solution used.Preferably, the concentration of conducting salt is less than 0.001moles/l. The solution used can be essentially free from conducting salt.

The product of stage (b) is often a modified organic compound salt. Ifnecessary to obtain the desired final product, further reactions can beperformed starting from the modified organic compound salt, for exampleto eliminate the charged group if necessary, or to modify certainsubstituents, for example by nucleophilic or electrophilic substitution.

The invention also concerns an organic compound salt corresponding tothe formulaR1R2ZC-T-Q-XY   (XXIII)wherein

-   X is a charged group as defined above,-   Y is a counter-ion as defined above,-   Z is a group capable of being substituted,-   R1 and R2 mean organic residues as defined above,-   T means a group containing a hetero atom selected among N—R4, O and    S, NR4 being as defined above, and-   Q means a connecting group as defined above, linking the hetero atom    and the charged group.

It has been found that the organic compound salt according to theinvention is an efficient intermediate for the production of organicsubstances, presenting substantial advantages as regards its solubilityin reaction solvents and allowing easy separation and purification ofthe products obtained. When the organic compound salt according to theinvention is an enantiomerically pure substance, it is an efficientintermediate for asymmetric synthesis.

The substituent Z in particular means a group capable of being replacedby nucleophilic substitution. Such groups can be selected for exampleamong the halogens, in particular chlorine or bromine, esters and alkoxygroups. Esters within the group Z are often selected among thefluorinated esters such as the fluoroacetates, thefluoroalkylsulphonates or the alkly- or aryl-sulphonates. Preferably,the esters are selected among trifluoroacetate,trifluoromethanesulphonate and p-tolylsulphonate. Alkoxy group s oftencontain 1, 2, 3 or 4 carbon atoms. The methoxy and ethoxy groups arepreferred. A methoxy group is quite particularly preferred as thesubstituent Z.

In a particular embodiment, Z is an O-acetate (OAc) group. It isunderstood that the combinations and preferences indicated above for theuse according to the invention apply equally to the extent that they areapplicable, to the organic compound salt according to the invention.

The organic compound salt according to the invention can be obtained bythe process according to the invention.

The organic compound salt according to the invention, in particular whenZ is methoxy, can be used in substitution reactions, in particularcatalysed by acids, in particular Lewis acids, preferably with asilylated reagent such as allyltrimethylsilane or trimethylsilyl cyanide(TMS

N) or with aromatics.

Specific examples of organic compounds obtained from the organiccompound salt according to the invention include natural or non-naturalamino acids such as proline and β-proline.

The following examples are intended to illustrate the invention, withouthowever limiting it.

EXAMPLE 1 Preparation of 2-(N-pyrrolidine)-N,N,N-triethylethaammoniumtetrafuoroborate (1)

3.82 moles of pyrrolidine were added to a solution of 1.92 moles ofchloroacetyl chloride in 600 ml of dichloromethane. The temperature wasmaintained at 0° C. The organic phase was washed with solutions ofsodium hydrogen sulphate and sodium carbonate and dried. Afterevaporation of the solvent, 242 g of N-(2-chloroacetyl)pyrrolidine wereobtained. 1.64 moles of this compound were dissolved in 500 ml oftoluene and 231 ml of triethylamine were added. This was heated underreflux for 3 hrs and after cooling 311.5 g of product were isolated inthe form of a precipitate. 119.07 g of the product obtained weredissolved in

250 ml of boiling dichloromethane in the presence of 7.21 g of HBF₄ (54%by weight in diethyl ether) and 112.55 g of2-N-pyrrolidine)-N,N,N-triethylethanaminium tetrafluoroborate (1) wereisolated.

EXAMPLE 2 Preparation of3-N-piperidine-N,N,N-triethylammoniopropanesulphonamidetetrafluoroborate (2)

By procedures analogous to Example 1, the compound (2) was obtained frompiperidine, 3-chloropropylsulphonyl chloride and triethylamine.

EXAMPLES 3 AND 4 Electrochemical Methoxylation

The compound (1) or (2) was dissolved in methanol. This solution wasintroduced into a non-compartmented cell of volume 150 ml equipped witha cylindrical platinum anode with an internal diameter of 9 mm, anexternal diameter of 11 mm and an effective length of

27.5 cm, and with a steel cathode. The distance between cathode andanode was 2 mm. The reaction was stopped at the moment when secondaryproducts appeared (selectivity of the order of 100%).

Under the stated conditions, the following results were obtained for thesynthesis of 2-(N-2′methoxypyrrolidine)-N,N,N-triethylethanammoniumtetrafluoroborate (1a) and3-N-2′methoxypiperidine-N,N,N-triethylammoniopropanesulphonamidetetrafluoroboxate (2a) respectively: Con- Electro- Com- centrationChemical chemical pound (moles/l) A/dm² T ° C. yield yield Voltage (1)0.74 6.7 30 90% 65% 4 V (1) 0.37 20 0 52% 68% 4 V (2) 0.15 6.7 30 71%40% 4 V

The methoxylated product (1a) or (2a) respectively was easily isolatedby evaporation of the methanol. Its purity was sufficient to allow itsuse for subsequent reactions.

EXAMPLE 5

1.06 g of (1a) were dissolved in 3 ml of dichloromethane in the presenceof 0.9 ml of trimethylsilyl cyanide and 100 μl of SnCl4 at 0° C. and themixture was stirred. The solution obtained was subjected to hydrolysiswith 6 ml of 6N HCl at a temperature of 100° C. It was filtered on anacidic ion exchanger column and eluted with aqueous NH3 (5%). A crudeproduct containing 0.25 g (57%) of proline was isolated.

EXAMPLE 6

In a procedure substantially similar to examples 3 and 4, a solution of10.15 g (Boc)ArgProOH in 60 ml glacial acetic acid was electrolysedduring 3 hours at 25° C. at a current density of 0.025 A/cm². An HPLCanalysis indicated 90% conversion of the starting material: 2.5 mmole ofthe crude product obtained by evaporation/lyophilisation was reacted atroom temperature with 9 mmole allyltrimethylsilane in dichloromethane inthe presence of 4 mmole TiCl4. The yield to (Boc)Arg(allyl)pyrrolidineamide was 70%.

1-29. (canceled)
 30. A method of carrying out an electrochemicalreaction to herein an organic compound salt of general formulaA-XY   (I) wherein a means an organic residue, X means a charged groupand Y means a counter-ion is used as a reagent in said electrochemicalreaction.
 31. The method according to claim 30, wherein the group X is acationic group.
 32. The method according to claim 31, wherein the groupX is NR₃ ⁺ and R is one or several organic residues.
 33. The methodaccording to claim 30, wherein the group Y is Br⁻, Cl⁻, ClO₄ ⁻, BF₄ ⁻,PF₆ ⁻, toluene-sulphonate (Tos⁻) or benzenesulphonate (PhSO3⁻).
 34. Themethod according to claim 33, wherein the group Y is a mixtureconsisting essentially of 90 to 99.5% by weight of at least one ionselected from the group consisting of ClO₄ ⁻, BF₄ ⁻, PF₆ ⁻, Tos⁻ andPhSO3⁻ and 0.5 to 10% by weight of Cl⁻.
 35. The method according toclaim 30, wherein the organic compound salt corresponds to the formulaR1R2R3C-T-Q-X Y wherein R1R2R3C means a substituted carbon atom, capableof reacting in the electrochemical reaction, T means an activating groupfor the electrochemical reaction and Q means a connecting group linkingthe activating group T and the charged group X.
 36. The method accordingto claim 35, wherein the group T is NR4, O or S wherein R4 is a hydrogenatom or an organic residue.
 37. The method according to claim 35,wherein the group Q is a linear or branched alkylene or cyclo-alkenegroup, optionally substituted with a functional group and optionallylinked to the group T by a functional selected from the group consistingof —(C═O)—, —N—(C═O)—, —O—(C═O)—, —(S═O)—, —N—(S═O)—, —SO₂—, —N—SO₂—,—(C═S)— and —N—(C═S)—.
 38. The method according to claim 35, wherein atleast R3 is hydrogen.
 39. The method according to claim 30, wherein theorganic compound salt comprises at least one stereogenic center and isenantiomerically pure.
 40. The method according to claim 35, wherein theorganic compound salt corresponds to the formulaR1R2R3C—NR4-Q-NR₃ ⁺Y⁻ wherein the group Q is a linear or branchedalkylene group, optionally substituted with a functional group andlinked to the group T by a functional selected from the group consistingof —(C═O)—, —N—(C═O)—, —O—(C═O)— and —SO₂—.
 41. A process for productionof an organic compound comprising (a) a stage preparing a solutioncontaining an organic compound salt of general formulaA-XY   (I) wherein A means an organic residue, X means a charged groupand Y means a counter-ion, in a solvent; (b) a stage subjecting thesolution to electrolysis in the presence of at least one co-reactantunder conditions sufficient to form the product of reaction of theorganic compound salt with the co-reactant.
 42. The process according toclaim 41, wherein stage (b) is an electrooxidation.
 43. The processaccording to claim 41, wherein stage (b) is carried out at a currentdensity of from 0.1 to 50 A/dm².
 44. The process according to claim 41,wherein stage (b) is carried out at a temperature of from −50 to 100° C.45. The process according to claim 41, wherein the solvent consistsessentially of co-reactant and said co-reactant is water, methanol,ethanol or acetic acid.
 46. The process according to claim 41, whereinthe organic compound salt is of the formulaR1R2R3C—NR4-Q-NR₃ ⁺Y⁻ wherein R1R2R3C means a substituted carbon atom,capable of reacting in the electrochemical reaction, the group Q is alinear or branched alkylene group, optionally substituted with afunctional group and linked to the group T by a functional selected fromthe group consisting of —(C═O)—, —N—(C═O)—, —O—(C═O)— and —SO₂— and Tmeans an activating group for the electrochemical reaction; and theco-reactant is methanol.
 47. The process according to claim 41, whereinthe co-reactant is acetic acid.
 48. The process according to claim 41,carried out in the substantial absence of conducting salt.
 49. Anorganic compound salt corresponding to the formulaR1R2ZC-T-Q-XY wherein X is a charged group, Y is a counter-ion, Z is agroup capable of being substituted, R1 and R2 mean organic residues, Tmeans a group containing a hetero atom selected from the groupconsisting of N—R4, O and S, wherein R4 is a hydrogen atom or an organicresidue, and Q means a connecting group linking the hetero atom and thecharged group.
 50. The organic compound salt according to claim 49,wherein the group T is N—R4.
 51. The organic compound salt according toclaim 49, wherein the group Q is a linear or branched alkylene group ora cycloalkylene group, optionally substituted by a functional group,preferably containing from 1 to 12 carbon atoms and optionally linked tothe group T by a functional group selected from the group consisting of—(C═O)—, —N—(C═O)—, —O—(C═O)—, —(S═O)—, —N—(S═O)—, —SO₂—, —N—SO₂—,—C═S)— and —N—(C═S)—.
 52. The organic compound salt according to claim51, wherein the group Q is linked to the group T by a functional groupselected from the group consisting of —(C═O)—, —N—(C═O)—, —O—(C═O)—,—SO₂— and —N—SO₂—.
 53. The organic compound salt according to claim 49,wherein the group X is a cationic group.
 54. The organic compound saltaccording to claim 49, wherein the group X is NR₃ ⁺ and R signifiesorganic residues.
 55. The organic compound salt according to claim 49,wherein the group Y is Br⁻, Cl⁻, ClO₄ ⁻, BF₄ ⁻, PF₆ ⁻, Tos⁻ or PhSO3⁻.56. The organic compound salt according to claim 49, wherein the group Zis methoxy.
 57. The organic compound salt according to claim 49,containing at least one stereogenic centre.
 58. A method of carrying outa substitution reaction, wherein an organic compound salt according toclaim 49 is used as starting material for the substitution reaction.